Electrohydraulic brake systems typically include a pump unit that is driven by an electric motor for implementing functions, such as an anti-lock brake system or a driving dynamics controller. For suppressing unwanted noise in the vehicle or implementing situation-dependent working ranges or control functions of the brake system, for example in the case of an emergency or in a mode arranged for comfort, highly accurate knowledge of the position and/or the revolution rate of the hydraulic pump or the rotor of the electrical machine that is provided for driving the pump is desired.
In this regard, in International Application Publication No. WO 02/060734 A1, a unit for detecting the revolution rate of the electric motor for an electronically regulated brake system is described, which comprises at least one sensor for determining the revolution rate of the electric motor or the shaft. Furthermore, the functionality of such an electric motor must be configured so that said motor can meet the requirement that is imposed on the brake system for a given on-board electrical system of a vehicle. A check as to whether said safety requirements are met during the ongoing operation of the brake system is also carried out in a known manner by means of such a position sensor, whereby for example detection of the revolution rate of the hydraulic pump can be carried out.
In particular, for determining the position of the hydraulic pump or of the rotor of the electrical machine that is provided for driving the pump, inductive sensors are used that as a result of the underlying physical measurement principle require frequencies determined by means of a resonant circuit for the operation thereof. This results in limitations for the system clock of the actuating and analyzing microcontroller unit (“MCU”) or power control unit (“PCU”), from which running time problems can result during operation.
As such, it is desirable to present a system and/or method that implement the determination of the position of the hydraulic pump or the electrical machine that is provided for operating the hydraulic pump without limitations on the system clock for the actuating and analyzing MCU and/or PCU. In addition, other desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.